Polymer flooding in Daqing oilfield has shifted to the type II oil layers with poorer physical properties. As the conventional partially hydrolyzed polyacrylamide（HPAM）for polymer flooding is prepared with clean water and then diluted with produced water，more polymer powders are consumed，leading to worse recovery factor. In order to reduce polymer consumption， improve the injectivity and effects of polymer flooding，a salt-resistant polymer with high molecular weight，AM/AANa/AMPSNa/ AMP（named polymer A），was synthesized with acrylamide（AM），2-acrylamido-2-methyl propanesulfonic acid（AMPS），and 1-acryloyl-4-methyl piperazine（AMP）. By optimizing the synthesis parameters，polymer A was firstly co-polymerized in water and then hydrolyzed with NaOH. General property evaluations for polymer A and HPAM with the same molecular weight were carried out. The results showed that the appropriate preparation condition of polymer A was obtained as follows：20%—21%，7.5%—10% and 0.1%—0.5% monomer dosages of AM，AMPS and AMP，0.01% initiators combination of K2S2O8-NaHSO3 and 2，2’-azobis［2- （2-imidazolin-2-yl）propane］ dihydrochloride（Va-044）dosage for total monomers in quality，0.2% chain transfer agent isopropyl alcohol dosage for total monomers in quality，2℃ initiation temperature. The salt-resistance，thermal stability，visco-elasticity and injectivity for polymer A were better than those of HPAM with the same molecular weight. The lower permeability limit for polymer A of 1000 mg/L was 112×10-3 μm2，which was lower than that of HPAM by 53×10-3 μm2. Natural core flooding experiment results showed that the enhanced recovery factor of polymer A was 4.2% higher than that of HPAM under the same consumption. Due to the better thermal stability，injectivity and higher recovery factor，polymer A was suitable for the efficient development of the type II oil layers in Daqing oilfield.