The invention relates to the field of distribution network protection, and in particular to a cooperation method and system of in-situ protection and regional protection of a distribution network. According to the invention, a current protection III section of in-situ protection is arranged and a flag value of a signal is determined according to the protection thereof, so as to determine the qualification of cooperation of in-situ protection and regional protection, in this way, the in-situ protection can be prevented against the trip without fault or network attacks effectively, and meanwhile a comprehensive tripping cooperation scheme among the in-situ protection, the current protection III section of the in-situ protection and the regional protection is designed. The regional protection in the invention has high reliability by itself, can effectively prevent protection misoperation brought by the abnormality of remote transmission of sampling information, and can also accelerate the in-situ protection and identify a high-resistance ground fault that cannot be identified by the in-situ protection.