Aiming at the problem of lack of research on optimizing thermal condition of ultraviolet spectrometers, a Rowland circle spectrometer with a detection range of 200 nm~450 nm and a full-band resolution of no less than 0.2 nm was designed, and optimized the thermal conditions of its optical chamber by coupling optical, thermal and structural simulations. The thermal simulation results showed that the temperature and temperature difference of the spectrometer base was increased with time in the absence of heating and inlet wind speed, and it was difficult to achieve thermal balance. The inlet wind speed of optical chamber was optimized, and it was found that when that was 0.8 m/s, the overall temperature was dropped to 36.103 ℃~39.859 ℃. Based on the calculation of thermal deformation between optical devices, the intercept of total thermal deformation of several optical devices was 0.203 mm. After refining the heating method, the top-layer heating was found to be the best way, the overall temperature was dropped to 34.241 ℃~36.139 ℃, and the intercept of total thermal deformation was reduced to 0.122 mm. The optical simulation results show that the optimized Rowland circle spectrometer can still clearly distinguish the two beams with a wavelength difference of 0.2 nm after thermal deformation.