Abstract: Aimed at the difficulty in detecting hardware Trojans inside IC chips,a novel idea about detecting Trojan circuits with side channel analysis is introduced.After formally defining the problem of detecting hardware Trojans in IC chips with side channel analysis,the differences between principle components analysis on side channel signals acquired from chips with Trojan circuits and without Trojan circuits were analyzed.Detection experiments with principle components analysis were taken out on a DES cipher chip implemented on a FPGA board.The results of experiments verified the effect of Hardware Trojans detection with principle components analysis on side channel signal.