Modification method for improving activity of catalytic cracking catalyst

The invention provides a modification method for improving the activity of a catalytic cracking catalyst. The modification method comprises the following steps: mixing catalyst particles, organic acid, ammonium salt, a phosphorus-containing compound and water and pulping; raising the temperature and pressurizing to react; filtering, washing with water and drying; then adding a magnesium-containingcompound into the catalyst particles and uniformly mixing; roasting to obtain the modified catalytic cracking catalyst. The modification method provided by the invention can be used for remarkably improving the activity of the catalyst and a preparation process is simple; the method provided by the invention is applicable to various types of catalysts, such as a semi-synthetic agent, a full-carclazyte catalyst and a balancing agent, and has a relatively wide applicable range.