Due to the low region-selectivity, the alkylation of 5-amino-4-cyano-pyrazole always bring forth the mixture of two substitution products. Based on the alkylation method, We start from the raw material of 3-amino-1H-pyrazole-4-carbonitrile, and compare the effect of solvents and deacid reagents on the region-selectivity and yield. Although the overall conversion yield doesn’t change so much among DMSO, DMF and CH3CN, the solvent of DMSO can distinctly improve the region-selectivity. The pure product of 5-amino-1-benzyl-4-cyano-pyrazole can be conveniently recrystallized from 95% ethanol with a separation yield of 62% when using DMSO and CsCO3 as reaction solvent and deacid reagent, respectively. Its chemical structure is characterized with 1H NMR and single crystal X Ray diffraction, which belongs to monoclinic space group P2(1)c with a = 1.4333 (3) nm, b = 0.6187(14) nm, c = 2.2389 (5) nm, α = 90°, β = 93.773(4)°, γ = 90°, V = 1.981.1(8) nm3, Z = 8, Dc = 1.329 g cm-3, λ = 0.71073 nm, μ (Mo Kα) = 0.085 mm-1, F (000) = 832.