Process of preparing a cracking catalyst, containing a rare-earth Y-zeolite and a support, which is characterized in that the rare-earth content in crystal lattice of the rare-earth Y-zeolite is 4-15 wt% of RE 2 O 3; the original unit cell size is 2.440-2.465 nm; the equilibrium unit cell size of the catalyst after 100% steam-aging treatment at 800°C for 17 hours is larger than 2.435 nm; the rare-earth atom content in the support is 1.0-8.0 wt% of the support, wherein the process comprises the following steps: Ultra-stabilizing a Y-zeolite, wherein the Y-zeolite is selected from a REY zeolite, a REHY zeolite, or a RENaY zeolite, wherein in case of the REY zeolite, its rare-earth content is from 10 to 18 % by weight of RE 2 O 3 and the Na 2 O content is not more than 3 wt%; in case of the REHY zeolite, its rare-earth content is from 6 to 14 % by weight of RE 2 O 3, and its Na 2 O content is not more than 6 wt%; in case of the RENaY zeolite, its rare-earth content is from 6 to 15 % by weight of RE 2 O 3, and its Na 2 O content is not more than 6 wt%; or alternatively, the Y-zeolite is obtained from a NaY zeolite with Si/Al ratio higher than 3.5 by exchanging the NaY zeolite and a rare-earth chloride solution in a weight ratio of NaY:RECl 3:H 2 O=1:0-1-0.25:5-15 at 80-90°C for 30 to 60 min under a pH more than 3.5; mixing the ultra-stabilized Y-zeolite, without washing, ion-exchanging and filtering, directly with the deionized water, pulping, and optionally milling to give a molecular sieve slurry; Mixing the molecular sieve slurry with a binder slurry and a clay and pulping, or pulping with the binder slurry and the clay in sequence, and forming by spray drying; and Washing the formed catalyst, filtering and drying, wherein the reaction procedure of ultra-stabilizing the Y-zeolite in the step comprises: drying the Y-zeolite until its water content is less than 10 wt%, letting in the SiCl 4 gas or the SiCl 4 gas carried by dry air with a weight ratio of SiCl 4 to the Y-zeolite being 0.1-0.9:1, reacting them at a temperature of 100-600°C for 10 min to 6 hours followed by purging the Y-zeolite with dry air for 5 min to 2 hours. Ultra-stabilizing a Y-zeolite, wherein the Y-zeolite is selected from a REY zeolite, a REHY zeolite, or a RENaY zeolite, wherein in case of the REY zeolite, its rare-earth content is from 10 to 18 % by weight of RE 2 O 3 and the Na 2 O content is not more than 3 wt%; in case of the REHY zeolite, its rare-earth content is from 6 to 14 % by weight of RE 2 O 3, and its Na 2 O content is not more than 6 wt%; in case of the RENaY zeolite, its rare-earth content is from 6 to 15 % by weight of RE 2 O 3, and its Na 2 O content is not more than 6 wt%; or alternatively, the Y-zeolite is obtained from a NaY zeolite with Si/Al ratio higher than 3.5 by exchanging the NaY zeolite and a rare-earth chloride solution in a weight ratio of NaY:RECl 3:H 2 O=1:0-1-0.25:5-15 at 80-90°C for 30 to 60 min under a pH more than 3.5; mixing the ultra-stabilized Y-zeolite, without washing, ion-exchanging and filtering, directly with the deionized water, pulping, and optionally milling to give a molecular sieve slurry; Mixing the molecular sieve slurry with a binder slurry and a clay and pulping, or pulping with the binder slurry and the clay in sequence, and forming by spray drying; and Washing the formed catalyst, filtering and drying,