Aiming at the requirement of nickel-based alloy weld cutting and groove processing in nuclear power maintenance site,a portable weld cutting device is designed. The device adopts milling principle and numerical control technology to realize rapid cutting and groove processing of weld in site. The problem of tool cooling which is not allowed to use coolant in site is solved by air-cooling technology. The structure design of the device is reasonable through experiments. It can be used in the field. According to the technical requirements of nickel-based alloy weld groove,the groove processing technology was studied and two kinds of processing technology were designed. They are the processing of the groove root R1 chamfer groove and the processing of 15° angles. The process test was carried out through the reasonable setting of cutting tool materials and processing parameters. The processing accuracy,processing stability and tool wear of the two process schemes were mainly observed and determined through the test. The optimum technological scheme and process parameters were obtained.