Abstract: OBJECTIVE To screen out the formulation of compound neostigmine in situ ophthalmic gel for myopia. METHODS Carbopol P934 and P940 were selected and researched as the matrixl of in situ pH-setting gel and its co-effect of combination with hydroxyl-propyl-methyl-cellulose(HPMC, K₄M). The formulation of base material of in situ ion-setting ophthalmic gel was gelrite. And the main matrix material of in situ thermo-setting gel was poloxamer P407 and P188. On the screening of the formulation, the viscosity of gel and the compatibility of ingredients were used as two indexes. RESULTS The applicative formulation of compound neostigmine in situ ophthalmic gel was thermo-setting gel which was including 24% poloxamer P407 and 10% poloxamer P188. CONCLUSION This formulation is feasibility, and this preparation has good properties of sustained release.