The navigation performance was studied for an agricultural robot based on laser radar between the crop rows with intra row spacing and without intra row spacing, especially in the absence of one side crop row. According to the crop information from the laser radar, the different navigation methods were developed to calculate navigation path and thus to determine the lateral error and heading angle error for the different type of the crop rows. Then the fuzzy logic control was used to control the robot to travel along the calculated navigation path. Tests were conducted in three replications respectively while the robot traveled between the evergreen tree rows with a missing distance of 4m in one side and the pear tree rows with a missing distance of 6.2m in one side. Results showed that, the robot traveled successfully, with the maximum navigation errors of 17.5cm and 28cm for the evergreen tree tests and the pear tree tests respectively, when the inter row spacing of the evergreen trees and the pear trees were not fixed in the respective test distance. Meanwhile, the missing distance in one side for the evergreen trees had no significant effect on the traveling of the robot, but it seemed to have an effect for the missing distance of the pear trees. According to the statistic data of the tests and the robot trajectories, it was shown that the control algorithm had ability to make the robot travel along the centerline of the crop rows. 