Based on simulated monaural and binaural room impulse responses, the relationship between Chinese speech intelligibility scores and speech transmission index (STI) including the effect of noise is investigated using a phonetically balanced test in virtual rooms. The results show that Chinese speech intelligibility scores increase monotonically with STI values. The correlation coefficients are 0.95, 0.90 and the standard deviation is 5.6%, 6.7% under diotic and dichotic listening conditions, respectively. Compared with diotic listening based on monaural room impulse responses, dichotic listening based on binaural room impulse responses can improve by 2.7dB signal-to-noise ratio for Chinese speech intelligibility. The STI method can better predict and evaluate Chinese speech intelligibility in rooms.