Abstract: The ever-developing Internet of things (IoT) brings the prosperity of wireless sensing and control application. In many scenarios, different wireless technologies coexist in the shared frequency medium as well as the physical space. Such wireless coexistence may lead to serious cross technology interference (CTI) problems, e.g. channel competition, signal collision, throughput degradation. Compared with traditional methods like interference avoidance, tolerance and concurrency mechanism, directly and timely information exchange among heterogeneous devices is therefore a fundamental requirement to ensure the usability, inter-operability and reliability of the IoT. Under this circumstance, cross technology communication (CTC) method thus becomes a hot topic in both academic and industrial field, which aims at directly exchanging data among heterogeneous devices that follow different standards. Most of existing research works focus on the enabling technology of CTC, but lack of thinking and summary of CTC methods. Based on the survey of recent studies in CTC method, we first analyze the background and significance of CTC method. We category existing methods as two classes including packet-level CTC and physical-level CTC, and introduce the application scenarios of CTC method. The potential research directions in this area are further discussed, which is promising to achieve cross-networks, cross-frequency, and cross-medium connections.