The isopressing charging technology with multi-runner device of logical network initiator was studied according to the structural features of small diameter, large aspect ratio, multi-corners of the high viscousity of PETN based putty explosives. The charging process conditions were determined accordingly i.e, pressure is 80 MPa and dwell time is 30 min. The influences of different groove dimensions (0.3 mm×0.3 mm~2.0 mm×2.0 mm) and different corner turning (108°~160°) on detonation velocity were investigated. The minimum groove size and the maximum cokner for propagation of explosion were investigated. The physical and chemical uniformity and wave synchronization for isopressing charging were also studied by experiments. The results show that the least groove dimension is 0.3 mm×0.3 mm, and the biggest degree of corner turning is 150°. The range of charge density is 1.504~1.507 g·cm^-3, and the charge composition deviation is 0.34%~0.56%, and the dispersion of the wave synchronization is between the 0.03~0.05 μs.