Abstract: For the Leikoupo Formation high-sulfur gas reservoir in western Sichuan Basin, which is deep, tight and highly heterogeneous, acid stimulation is the main technique for enhancing the recovery. However, highly-deviated well, coupling with high reservoir formation fracture pressure, leads to frequent downhole complexities, such as premature setting, seal failure, release failure, and slip loss, during stimulation and testing. To adress these problems, the hydraulic packer is used; the cone-slip sleeve distance of the packer is adjusted and the hydraulic anchoring reliability is analyzed to avoid packer failure. The axial force at the packer in highly-deviated well is accurately calculated through numerical analysis to ensure the string reserves a sufficient tensile margin at the time of release. Analysis of wells that were found abnormal in early tests reveals that the detonative power during perforation may induce a premature setting of the packer; so, ultra-deep highly-deviated well is not qualified for simultaneous operation, but should be tested with the string running after perforation. This technology has been applied to some marine ultra-deep high-sulfur highly-deviated wells (e.g. PZ3-5D) in western Sichuan Basin with high success, and it is referential for testing of highly-deviated wells in formations with high fracture pressure.