Gradient measurement has a great significance to improve the resolution of electromagnetic exploration and to suppress the environmental noise and interference. There are two types of methods to measure gradient filed, measuring differential signal directly by hardware and calculating difference between two channels of absolute vector field. In this paper, the specific implementation of this two modes are achieved, and the results of this two methods are compared. Besides the sources of error and methods to suppress noise are explored. The research shows that discordance between channels, especially the phase difference is the key to influence measurement accuracy. As the hardware mode acquires differential signal by hardware directly, it is difficult to eliminate the error caused by discordance between channels according to calibration method. Moreover, the error magnitude increases with the decrease of the gradient too rapidly to measure the gradient field. The software mode, which acquires gradient field by software difference method after measuring absolute field, can achieve smaller error, and the measurement accuracy can be further improved after the channel calibration. In one word, if it’s difficult to ensure the highly discordance between channels, the software mode is the optimal way to realize the measurement of electromagnetic gradient, which can obtain the absolute field simultaneously to aid gradient data interpretation. The results of this study provide a useful reference for the development of electromagnetic gradient system. According to the method, array receivers are designed for frequencydomain controlledsource electromagnetic gradient method, and the experimental results in Jiangsu verifies the superiority of the measurement method.