This review aims to ascertain the effects of mHealth on negative emotions among parents of preterm infants and analyze the current state of mHealth services in this context. Caring for preterm infants often engenders negative emotions in parents, such as anxiety, depression, and stress. Mobile Health (mHealth) services offer potential benefits for preterm infant care. However, there are several uncertainties regarding the impact of mHealth services on parental emotions. Randomized controlled trial (RCT) and quasi-RCT were published in English and Chinese until 2023 and are available in the electronic databases of MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Web of Science, Cumulative Index to Nursing and Allied Health Literature (CINHAHL), Chinese Biomedical Literature Database, China National Knowledge Infrastructure, Wanfang Database, and China Science and Technology Journal Database were reviewed. Review Manager 5.4 was employed for random-effects meta-analysis. Seven RCTs and 6 quasi-RCTs with high risks were included, most of them were based on small sample size and single-centered. Meta-analysis demonstrated that mHealth interventions mitigated negative emotions, including anxiety (standard mean difference [SMD]=-1.07; 95% confidence interval [CI], -1.47 to -0.66; P<0.0001), depression (SMD=-1.94; 95% CI, -3.01 to -0.86; P<0.0001), and stress (SMD=-1.24; 95% CI, -2.07 to -0.40; P<0.0001), among parents of preterm infants. It is recommended to develop independent specialized software for mHealth, enhance theoretical underpinnings, and standardize practical protocols. Incorporating early recognition and screening of negative emotions within mHealth could offer comprehensive support for the mental health of parents with preterm infants. The mHealth-based interventions are needed to focus on the parents' emotional needs and minimize the impacts associated with mental stress.