Twenty pepper materials (numbered from A1 to A20) with different heat-tolerance were used in this study and 13 physiological indicators of the pepper seedlings under heat stress(40 ℃ for 16 h at day and 30 ℃ for 8 h at night) were taken to analyze the heat-tolerance of pepper by principal component analysis, subordinative function analysis, cluster analysis and regression analysis. The results showed that 20 pepper materials were divided into four categories, strongly heat-tolerance (D≥0.6), mildly heat-tolerance (0.55≤D＜0.6), heat-sensitive (0.45≤D＜0.55), strongly heat-sensitive (0.35≤D＜0.45), and the D value represents the average of membership function of comprehensive index. A13 (17CL30), A15 (11L209F2-3-2-1), A7 (SJ07-23-2-3-1), A11(16CT32), A12 (H1306-1-2-1), A19 (LS22) and A16 (16HL28) were identified as heat-tolerance materials, which can be used as the parent material in breeding of a new variety of pepper with heat-tolerance.