The utilization coefficient of irrigation water were calculated by using the head-tail method, which was focused on 11 small-sized irrigation areas during 2013 and 2014 in Shanghai City. The impact laws and degree of different influence factors which affected utilization coefficient of irrigation water were investigated with the principal component analysis. The results showed that the utilization coefficient of irrigation water in 9 of 11 sampled irrigation areas were above 0.7,of which, the maximum was 0.861, which was significant higher than average level of the whole country. Besides, rice cultivation proportion, seepage-proofing canal lengths, the lining rate of canal and the area ratio of water-saving irrigation had greater impacts on the utilization coefficient of irrigation water, and seepage-proofing canal lengths, the lining rate of canal and the area ratio of water-saving irrigation had great positive contribution rates, while rice cultivation proportion have great negative contribution rate. The utilization coefficients of irrigation water could be increased by optimizing the cropping structure, carrying out water-saving irrigation project construction as before, and vigorously extending water-saving irrigation technology.