Helicopter transient electromagnetic system (HTEM) is an important tool for geophysical prospecting and detection in complex and harsh environment. The spatial sampling is dense and there is large amount of data to be interpreted. Taken the consideration of computing time, 1D inversion is mostly used in practical. This paper focuses on the HTEM system fixed with large circular transmitting loop, and develops Occam inversion for such system. In order to improve the computation accuracy, this paper derives Jacobian’s matrix in analytic way. A software for HTEM’s Occam inversion is developed to cater to the needs in field test. It can achieve data preprocessing and data inversion after selecting the receiver point. This software has a satisfying result when applied to the field data inversion.