Abstract: The surface calcification is a kind of deposit on the earth, which is an important deposit type of land calcium carbonate. For a long time, the hydrodynamic formation cause of land calcium carbonate deposit is familiar to the researchers. The research of the biological cause of the formation is relatively fewer. In fact, the biological cause should be not ignored as well, especially algous deposit process. From imitating for field hydrodynamic force condition, taking the bluegreen algae for example, the research makes a biological deposit test under the different hydrodynamic force condition. From the test, we get optimum hydrodynamic condition of algae growth and their calcification rate, that is under the rate of 0~60 rpm, under the excessive strong , the growth of bluegreen algae will be restrained, and reduce the deposit rate of calcium carbonate. Under the condition of waterfall, hydrodynamic force is strong, in calcium carbonate depositing process, hydrodynamic formation cause of land calcium carbonate deposit is the lead cause; Under the weaker hydrodynamic condition, such as in river bed, biological calcification deposit will be the lead cause. Therefore, hydrodynamicbiological cause viewpoint has been proposed in the article. From the field algous samples, the calcium carbonate depositing test has been done under the different water hydrodynamic conditions. The test results show that under the faster water condition, most calcium carbonate will deposit very quick，and fewer algae calcium carbonate will precipitate because of adverse living environment under the condition. And under the slower water condition, because of being avail for algae’s living, more algae calcium carbonate will precipitate, and few calcium carbonate will deposit under the condition without algae. Also, under the motionless condition, contribution of calcium carbonate deposit have been compared in the article between the algous environment and without algous environment. The article presents , while without algous, under the motionless condition, the calcium carbonate depositing is controlled by liquid equilibrium state, over saturation liquor will keep the deposition going, unless the liquor is saturated. But, while algous join, under the motionless condition, the calcium carbonate depositing may not be controlled by liquid equilibrium state, algous calcium carbonate deposit will keep going，even if it is saturated. So, under the faster flow condition, without doubt, fast flow makes CO2 in liquor overflow，calcium carbonate will deposit in quantity，while the contribute from algous calcium carbonate deposit is few. Under the motionless condition,Mechanism of CO2 overflowing almost disappear, or weak, corresponding calcium carbonate deposit is few, and algous calcium carbonate deposit is main. Then, in nature, largely stromatolite may indicate a quiet deposit environment.
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