The radar chart analysis is an application of the phase identification method, which compares standard well log curve with the well logging curves of non-taken coring. It is the interpretation technique to identify lithology and the nature of the oil and gas in unknown wells by curve differences comparative method or area method. This paper describes the principle of the radar chart analysis method and the running process of radar chart drawing software and verifies this method with practical examples. Practice shows that, in log interpretation, the radar chart analysis can accurately determine formation lithology of the well profile and identify the nature of reservoir fluids. With the help of the radar chart drawing program, the comparative analysis of the characteristics of the formation logging response can be well completed.