With the development of heterogeneous computing technology, heterogeneous fusion processors, such as CPU-GPU integrated processors, have been fully developed in recent years, and arouse attention from both academia and industry. The fusion of different devices has several advantages. For example, all devices share the same memory and can have fine-grained cooperation. However, many system programming challenges and optimization challenges have emerged. To take full advantage of the capacity of heterogeneous fusion processors, it is needed to utilize features of heterogeneous fusion processors such as shared memory, and to perform architecture optimizations to different devices according to different applications. The research work related to heterogeneous fusion processors is first analyzed and summarized. Second, the related work about performance analysis is introduced. Third, the optimizations on heterogeneous fusion processors are summarized. A summarization for the applications that utilize heterogeneous fusion processors is also provided. At last, the future directions are provided on heterogeneous fusion processors and conclusion is given.