Using He-Ne laser to irradiate macrophages, the _i distribution of the single macrophage and the immunocompetence are studied in real-time by change laser power and irradiated time. Experimental result indicated that the _i of the macrophages increases with time and reaches the max value then decreases to preliminary station gradually, presenting cricoid-scalar distribution, the best strong in center and decrease radially. Different laser doses have different impact to macrophages _i and immunocompetence. With same laser wavelength and dose but different laser power, the change of [Ca2+]i and immunocompetence are also different obviously. When laser power is 0.16 mW, the max value of [Ca2+]i is almost six folds higher than that of the laser power is 0.40 mW. The max value of [Ca2+]i corresponding the station of the best strong immunocompetence. The action mechanism is primary discussed in this papaer.