Citrinin is a nephrotoxic metabolite produced by nature filamentous fungi of the genera Monascus, which has been encountered as a natural contaminant in grains, food, feedstuffs, as well as biological fluids. However, it is recognized as an antibacterial metabolite. Citrinin was investigated in type culture of induced mutation Monascus. purpureus TISTR 3541 by HPLC to test citrinin producing ability along with pigment production. M. purpureus TISTR 3541 was mutated by ultrasonic wave inducing at 28°C, 45 kHz for 2 min to generate mutants for 5 generations. The results indicated that content of the citrinin was significantly increased as the induced mutation increasing from 12.72 % in G2 to 74.70 % in G5 compared with those from the wild type strain. Comparison result on the mutant generation effect in pigment production, statistical analysis showed that mutant TISTR 3541 G5 was able to produce significantly higher pigment than wild type (p-values < 0.0001). Red pigment stability was also evaluated. Results found that red color of TISTR 3541 G4 mutant was the most stable generation at pH when compared to G5, G1, G2 and G3 with the stability increase more than G0 (60.00, 47.30, 33.50, 24.43, and 2.31 time, respectively). Temperature stability of red pigment revealed that TISTR 3541 G1 mutant was more stable at 4°C than G3, G2, G5 and G4 with 124.00, 62.00, 50.71, 41.50 and 33.42 times, respectively when compared to G0. In the resistance to solvent, the result exhibited that all mutants in ethyl ether increased the stability more than G0.