All-optical diode is one of the key devices of future optical communication and photonic computer.In this paper,the nonreciprocal optical transmission characteristics of a new-type all-optical diode based on nonlinear photonic crystal (PC) are analyzed by means of finite difference time domain,and two ultrashort pulse lasers are used to pump the PC directly-coupled microcavity and the side-coupled microcavity,respectively,so that the non- linear optical bistable state of the two microcavities can be accurately adjusted and a high-performance optical di- ode,which is of a unidirectional transmission rate up to 90% and a forward-reverse transmission contrast ratio of more than 80,is realized in a broad operating bandwidth of more than 0. 44nm (dozens of times that in the litera- ture).