The large dynamic range and high performance of temperature and humidity profile lidar made it a popular tool for monitoring the atmospheric environment. In this study, we carried out an accurate analysis of the key components of the lidar system, including lasers, the emitting and receiving light paths, and photodetectors. We combined the validation of simulations with experimental testing, and then the applicability indicators and necessary conditions in accordance were suggested. For the frequency stability of the laser, when the wavelength shift is less than 0.15%, the measurement accuracy of the system can be guaranteed to be less than 5%. The degree of near-field signal distortion will be significantly impacted by the size of the geometric factor’s transition zone. The introduced measurement error is less than 2% when the deviation angle of the emission axis is less than 0.1 mrad. It has been tested that selecting a low-sensitivity detector can help to improve the sensitivity of temperature detection since this channel is sensitive to the detector’s nonlinearity. To enhance lidar’s detection capabilities and direct the lidar system design process, it is beneficial to analyze the precision of the key components.