To investigate the correlation between leaf SPAD value and chlorophyll content of squash,leaf SPAD value and chlorophyll content were determined by SPAD chlorophyll meter and alcohol-acetone extraction respectively. Results showed that there was extremely significant correlation among chlorophyll a,chlorophyll b and total chlorophyll content and SPAD value in the four squash varieties. In terms of the correlation between SPAD and chlorophyll a, the optimal mathematical model for ‘Banli summer squash’, ‘Shengyu306’, ‘Fengkangzao’, and ‘Xiangjiao summer squash’was y = 0.8252 e^{0. 0109 x}（r = 0.8057 ^**）, y = 0.2719 e^{0. 0344 x}（r= 0.8854 ^**）, y = 0.6186 e^{0. 0173 x}（0.7831 ^**）, y = 0.9181 ln（x）-2.1481（r = 0.7901 ^**）. In terms of the correlation between SPAD and chlorophyll b, the optimal mathematical model for ‘Banli summer squash’, ‘Shengyu 306’, ‘Fengkangzao’, and ‘Xiangjiao summer squash’was y=0.6069 e^{0. 0081 x}（r=0.7845^**）, y=0.6069 e^0.0081x（r=0.6473^**）, y=0.4712 e^{0.0129 x}（r=0.7868^**）, y=0.7384 ln（x）-1.8869（r=0.8357^**）. In terms of the correlation of SPAD value and chlorophyll content of total, the optimal mathematical model for ‘Banli summer squash’, ‘Shengyu 306’, ‘Fengkangzao’, and ‘Xiangjiao summer squash’was y=1.4989e^{0. 009 x}（r=0.8095^**）, y=0.5225e^{0.0309 x}（r=0.8200^**）, y=1.0843e^{0.0156 x}（r=0.7989^**）, y=1.6565ln（x）-4.0349（r=0.8154^**）.