The magnetometer based on ensembles of NV centers has attracted much attention within the fields of quantum information. As a new technology, NV center magnetometer can detect magnetic field with high sensitivity and spatial resolution at room temperature, which has broad application prospects in the fields of weak magnetic field measurement. We expect the highest sensitivity to be achieved by any method; the factors affecting the sensitivity are the contrast and linewidth, which depend on the microwave (MW) and light powers; are critical for optimizing magnetometer sensitivity based on high-density nitrogen vacancy (NV) centers in diamond. In this paper, we report a study of the coherent population oscillation based on ensembles of NV centers by using two microwave channels to control quantum state of NV centers. The notion of coherent population oscillation is widely used in the atomic physics/quantum optics community but is essentially unknown in the EPR/ODMRcommunity. A home-made magnetic field detection system was set up to sense the external magnetic field and the experimental results of optically detected magnetic resonance show that the phenomenon of “hole burning” and the linewidth at the peak becomes narrower. We attribute the spectra to coherent population oscillations induced by the two nearly degenerate microwave fields. At the same time, because the sensitivity is related to the slope of signal modulation, the detected signal was demodulated with a lock-in amplifier referenced to the modulation frequency by a signal generator, the slope of microwave modulation signal increased from the experimental results. Under the condition of continuous wave experiment, both microwave channels are tuned to the resonance frequency between the ground state 3A2 of NV center ensembles, and the pump of one channel is set to a given frequency (ms=0ms=±1), and the probe is set to sweep frequency. In this experiment, we attribute the resonances occurring on the same transition to the coherent population oscillations (CPO) resulting from interference (beating) between two coherent electromagnetic fields (ms=0ms=+1). Via this method, the observed optically detected magnetic resonance spectra showed a complex narrow linewidth structure and whether the shape of the hole would change under different microwave conditions was tested. When the detection microwave power is constant, the lower the pump microwave power, the narrower the linewidth. When the pump microwave power is constant and the microwave frequency is changed, the hole burning always appears at the changed microwave frequency, and the effect occurs only for beat frequencies within the range determined by the population relaxation times. Finally, we modulated the optically detected magnetic resonance signal by using sine wave. Because the sensitivity of NV color center ensemble magnetic detection is inversely proportional to the maximum slope of demodulation curve, it is found that the modulation slope of coherent layout phenomenon was increased by 20%, which further improved the shot-noise-limited sensitivity of DC. This article is just a basic experiment about coherent population oscillation, however it has a good application for achieving high precision measurement in the future and provides a good support for reducing linewidth.