Abstract: The influencing factors of C₃ yield were analyzed on a domestic 1 200×10³ m³/d light hydrocarbon recovery unit with direct heat exchange (DHX) process. Under the condition of existing equipment, the simulation was done by Aspen HYSYS. The sensitivity of the key parameters was analyzed, which weighed the relationship between C₃ yield and energy consumption. According to the analysis results, some conclusions were obtained: the optimum operating temperature was -42 ℃ for low temperature separator, the optimum operating temperature was -70 ℃ for the reflux of DHX tower. Furthermore, the expansion ratio of expander is a key factor to affect the yield of C₃, but it is unfavorable to adjust the expansion ratio of expander without new feed gas compressor or outlet natural gas compressor. The main reason of temperature fluctuation, pipeline effusion, even cut-out of C₂ tower was found by the calculation of the pipeline from C₂ tower to DHX tower. Based on the results of the above analysis, three measures were proposed to improve the C₃ yield, which included increasing the heat exchanger area to reduce the operating temperature of low temperature separator, adjusting DHX tower feeding process to reduce loss of C₃, adding gas-liquid separating pot to avoid gas-liquid two-phase flow boosting, and decreasing the pressure loss. The C₃ yield could be raised from 67.1% to 82.3%, and the temperature fluctuation, pipeline effusion, even cut-out of C₂ tower could be effectively solved. The security and stability of unit were enhanced.