The micelles behavior of amphiphilic block copolymer P(Styrene|b|acrylic acid), in aqueous solvent was studied by dynamic light scattering and TEM techniques. The diameters of micelle decreased and then increased with the decrease of the pH of the solution, and the similar phenomenon was also detected with the increase of the concentration of the calcium ion. Without added acid, the micelles were small spheres of low polydispersity with an average diameter 48 nm. When the value of pH was less than 2, the micelles were unstable. It was found that the Ca+{2+} was linked with the carboxyl in the same micelle when the concentration of the CaCl-2 was less than 0^2 mg/mL. The diameter of micelle was smaller than the one without Ca+{2+}. The Ca+{2+} was linked with the carboxyl between the different micelles when the concentration of the CaCl-2 was more than 0^5 mg/mL and the micelle was unstable. The diameters of micelles(from 37 nm to 100 nm) can be controlled by adding an appropriate concentration of CaCl-2 between 0^2_0^5 mg/mL. The micelles behavior of amphiphilic block copolymer P (Styrene | b | acrylic acid), in aqueous solvent was studied by dynamic light scattering and TEM techniques. The diameters of micelle decreased and then increased with the decrease of the pH of the the same as was was detected with the increase of the concentration of the calcium ion. Without added acid, the micelles were small spheres of low polydispersity with an average diameter of 48 nm. micelles were unstable. It was found that the Ca + {2 + was was linked with the carboxyl in the same micelle when the concentration of the CaCl - 2 was less than 0 ^ 2 mg / mL. The diameter of micelle was smaller than the one without Ca + {2 + . The Ca + {2 + } was linked with the carboxyl between the different micelles when the concentration of the CaCl - 2 was more than 0 ^ 5 mg / mL and the micelle was unstable. The diameters of micelles (from 37 nm to 100 nm) can be controlled by adding an appropriate concentration of CaCl - 2 between 0 ^ 2 _ 0 ^ 5 mg / mL.