The invention relates to a method of using an F type well group to exploit non-diagenetic type natural gas hydrates. The method includes the following steps that step 1, a slant well is drilled, the slant well is slantly drilled from the upper face of an unstable stratum to a target spot A in an underling stable stratum of a natural gas hydrate reservoir, and then a casing pipe is lowered and cement is poured for well completion; step 2, a horizontal well is drilled and is provided with a vertical well section, a deflecting well section, an up-warp well section and a horizontal well section and the vertical well section is located on one side of the well bottom, in the slant direction, of the slant well; step 3, fracturing sand control construction is carried out on the horizontal well, the condition that fracturing seams extend into the reservoir is required, and chemical sand control agents are injected into the fracturing seams and the reservoir; and step 4, the slant well is closedby using a well opening, the horizontal well is opened, and the natural gas hydrates are exploited by adopting CO2 replacement or heat injection or depressurization or a mixing method. The stabilityand patency of a well shaft are improved, the contact area of the well shaft and the reservoir is enlarged, and changing of the phase state of the natural gas hydrates occurs in the stable well shaft;on the one hand, complex accidents and even a disaster caused by uncontrollable shakeout and the uncontrollable changing of the phase state of the natural gas hydrates and the unstable well shaft canbe effectively avoided, and on the other hand, well yield and economic benefits of the natural gas hydrates can be effectively improved.