A good Samaritan was stabbed on a Lower Manhattan subway car after he tried to break up a fight between two women early Wednesday, cops said. 

The 31-year-old man intervened in the brawl on a southbound No. 6 train at the Brooklyn Bridge-City Hall station just before 6 a.m., police said. 

“Why are you hitting on her?” he asked, according to police sources.

One of the brawling women, believed to be in her 20s, then pulled out a knife and repeatedly stabbed him in the shoulder, neck and arm, authorities said. 

The victim was taken to Bellevue Hospital with non-life-threatening injuries, cops said. 

A knife was recovered, authorities said. 

Police were looking for the alleged stabber, who cops say had short black hair and wore green shorts.