Disclosed are applications of substituent benzyloxy group containing ether compounds represented by general formula I for preparing antitumor drugs. The definitions of the substituent groups in the formula are provided in the specification. The compounds having general formula I have desirable antitumor activity, particularly, and have excellent activity against leukemia strain HL-60, lung cancer A549, H157, H460, H520, bladder cancer T24,J82, prostate cancer LNCap, PC-3, rectal cancer HCT8,HCT116,RkO, and the like.