The intensity noise characteristics of a compact and low-noise intracavity frequency-doubled single-frequency Nd:YAP/KTP laser is analyzed theoretically and experimentally. By reducing the transmission rate at 1080 nm of the output coupling mirror, optimizing the parameters of the resonator, and so on. The intracavity losses decrease to 0.9%. As a result, the intensity noise of the output beam, which induced from vacuum fluctuations, is reduced to a lower level. When the transmission rate at 1080 nm of the output coupling is 0.2%, an output power of 420/60 mW at 540/1080 nm dual wavelengths single-frequency laser is manufactured, and its intensity noise is reduced to shot noise limit above 1.5 MHz.