Based on the near infrared absorption spectroscopy characteristics of CO2, an optical parametric oscillation (OPO) and amplification (OPA) system is proposed for the monitoring of CO2 emission sources. The system is composed of laser dual-seed source injected into OPO, OPO and OPA, narrow bandwidth laser seeded and pulsed Nd:YAG laser transmitting fundamental frequency, a dual-channel wavelength meter with high accuracy and frequency stability etc, which can output alternately dual-wavelength laser beams at 1.572 μm. After the system is debugged preliminarily, the conversion efficiency near 25% is obtained when the pump pulse energy is 326 mJ, and pulse energy is near 80 mJ, which can meet the need of ground-based differential absorption lidar measurements of CO2 concentration profiles in troposphere.