Abstract: The threshold of the traditional Canny algorithm needs to be set by manual,and its computation is complex.To overcome these shortcomings of the traditional Canny algorithm,A method of threshold-adaptable edge detection and its implementation in hardware are proposed.Based on the gradient histogram,the two thresholds can be found and the edge can be detected automatically.It is meanwhile recommended that an implementation of this edge detection is carried on in field programmable gate array(FPGA).Experiments show that compared with the traditional Canny algorithm,this method can detect edge automatically and needs much less time consumption.