In view of low dimensional discrete chaotic systems' weak resistance to degradation, we put forward a new 4D discrete hyperchaotic map, which has larger Lyapunov exponents, wider chaotic range, better distribution and more complexity than the hyperchaotic Lorenz system. In addition, the chaotic signals generated by the proposed map pass the NIST test and are implemented on the hardware DSP. Finally, we combine our chaotic map and dynamic expand XOR (eXOR) and XOR operation in image encryption. The experimental results express that compared with some other methods, the presented encryption algorithm has higher security and can resist common attacks.