In the construction of the conductor casing and surface casing cementing, due to the low bottom hole circulating temperature(BHCT), the compressing strength of oil well cement development slowly, waiting on cement(WOC)need a long time, an increase of drilling costs, could easily lead to annular gas channeling, and have a bad effect on cement job quality and safety of operations. For the type of current domestic oil well cement early strength agent are few, The effective of some early strength agent are not satisfied. Some are Corrosive to the casing, and have a great influence on slurry rheology and other issues. Laboratory selected a new compound early strength agent with on chlorine and containing crystal seed.The thickening time, compressive strength, settlement stability properties, anti-gas channeling ability and other parameters of the slurry are tested. The results show that: There are some advantages of the cement slurry like right-angle-set, low temperature rapid strength, excellent settlement stability properties, and strong ability of anti-gas channeling and form a low density cement slurry which density range from 1.30 to 1.90g/cm3, it provide a reliable guarantee to cementing operation in shallow well with low-temperature under the different reservoir pressure.