The woman was found badly injured, lying next to her 13-month-old daughter on the intersection of Edinger Avenue and Raitt Street Thursday.
The victim, identified as 21-year-old Gloria Sanchez, later died from her injuries.
Fransico Montano turned himself in Friday, but has not been cooperative. The suspect's black Toyota Rav4 was seen leaving the scene of the crime.
The couple's child was found scratched up and has since been placed under the care of Orange County Social Services.
Police believe the woman was either pushed or jumped off a vehicle with the child in her arms.
Montano is being held on $200,000 bail. Officials believe he may be a flight risk.
Anyone with information in this case was urged to contact Santa Ana police at (714) 245-8665.