Abstract: AIM　A series of 4-styrylcoumarin derivatives had been designed and synthesized in order to find compounds of antitumor activities by screening. METHODS　Title compounds (1-20) were synthesized by Phase-Transfer Wittig reaction or Wittig-Horner reaction, and screened by several antitumor models in vitro. Their structures were determined by ¹HNMR, MS and elemental analysis. RESULTS　Twenty compounds (1-20) are new compounds. Compound 18 had effects on KB cell lines in vitro. CONCLUSION It was seen that compound 18 had certain antitumor activities, and it was worth further studying.