Abstract: Research purposes: The transient electromagnetic method is more sensitive to low resistance body，so this method often be used in the survey of coal mine goaf and groundwater. But in the actual investigation, affected by terrain and surface construction, transmitter loop is often not laid regularly and the current method of calculation is applicable to the regular emission source. Based on the magnetic dipole field superimposed ideas， calculations of transient electromagnetic response of the irregular emission source is carried out，the purpose is to achieve a transient irregular emission source simulation of electromagnetic response，which lays the foundation for the inversion calculation，so that the process can be better applied to complex terrain reconnaissance applications, to solve complex terrain limitations on survey methods. Research conclusions:(1) By comparison with the results of circular and rectangular emission source, the idea based on magnetic dipoles superimposed to calculate the irregular emission source transient electromagnetic response is correct， the calculation method is feasible. （2) In this paper，we achieve the calculation of transient electromagnetic response of irregular emission sources，so that transient electromagnetic method can adapt to the complex terrain，and solve the problem of irregular layout of field emission source， which has practical value. (3) This research has a guiding significance for survey of the railway mining goaf and groundwater under the complex terrain condition.