In this study, some low-titanium aluminum alloys produced by electrolysis were prepared and the effect of various titanium contents on microstructure and tensile property of Zn-Al alloy was investigated. The test results showed that addition of titanium by electrolysis is an effective way to refine the grain size of Zn-Al alloy. As the titanium content is 0.04 wt%, the grain size becomes to be a minimum value and the tensile property of the alloy reaches to the maximum. Electrolysis showed that titanium atoms are to be some inherent particles in low-titanium aluminum alloy. These titanium atoms enter into the aluminum melt liquid and spread to the whole melt rapidly under stirring action of electromagnetic field of the electric current. The heterogeneous phase nuclei are high melting TiC and TiAl3 particles formed from in-situ precipitating trace C and Ti during cooling process. These in-situ precipitating heterogeneous nucleation sites with small dimension, high dispersity, cleaning interface and fine soakage with melt, have better capacity of heterogeneous nucleation than of exotic particles. It may inhibit grain growth faster and more effective in pinning dislocations, grain boundaries or sub-boundaries.