Resistant strains of Tetranychus viennensis Zacher were selected and developed in the laboratory by treating the basic strains collected from several peach trees on the campus of Gansu Agricultural University with omethoate, fenpropathrin and propargite. The rate of resistance development after 15 sprays was the quickest in the fenpropathrin-resistant (FR) strain (192-fold increase), the second in the propargite-resistant (PR) strain (130-fold increase) and the slowest in the omethoate-resistant (OR) strain (31-fold increase). Tests on crossresistance to 14 insecticides among the three resistant strains show that OR strain had no cross-resistance to fenpropathrin (the resistance factor, RF LC₅₀ (R)/LC₅₀ (S) 0.7) and bifenthrin (RF 0.89), but had cross-resistance to monocrotophos (RF 13.2), quinalphos (RF 16.5) and isocarbophos (RF 16.9), FR strain had cross-resistance to bifenthrin (RF8.1), cyhalothrin (RF18.4) and quinalphos (RF 6.7), but no cross-resistance to pyridaben (RF 0.71) and slight cross-resistance to dicofol (RF4.9), PR strain had no cross-resistant to cyhalothrin (RF 0.9) and yamanchun (RF 0.93), but had cross-resistance to quinalphos (RF 6.7).