Smith scored in the eighth minute, beating China goalkeeper Xu Huan off a pass from Rodman. It was Smith's 15th international goal in 37 national team appearances.
Horan made it 2-0 in the 52nd minute, striking the ball from distance before it bounced into the goal past Xu. It was her 30th goal.
Trinity Rodman had a hand in all three goals as the USWNT defeated China.
Brennan Asplen/USSF/Getty Images for USSF
Rodman capped the scoring in the 77th with an assist from Jaedyn Shaw. Rodman celebrated with a cheeky dance in front of the goal.
Among the players called up for the matches were three teenagers: Shaw, Olivia Moultrie, and Alyssa Thompson. It was also the first roster appearance for Jenna Nighswonger, who plays for Gotham FC in the National Women's Soccer League, and Paris Saint-Germain midfielder Korbin Albert.
Moultrie and Nighswonger both made their U.S. debuts as second-half substitutes.
Kilgore chose the roster in consultation with U.S. Soccer sporting director Matt Crocker and Emma Hayes, the new coach who will join the team in May after finishing out the season with Chelsea.
Hayes visited the team during the training camp ahead of the two final matches.
Veteran defender Abby Dahlkemper started against China, making her first appearance for the team in 599 days after having back surgery in October 2022.
Also returning to the starting lineup was Rose Lavelle, who hadn't played with the team since the World Cup because of an injury. Lavelle played as a winger in Kilgore's 4-3-3 formation.
The Steel Roses, ranked 15th in the world, were runners-up in the 1999 World Cup, won by the United States at the Rose Bowl.
Wang Jun served as interim coach for China. Former coach Shui Qingxia was dismissed after the Steel Roses failed to qualify for the Olympics.