The onset of malignant solid tumors in infants is insidious and difficult to diagnose in time. The purpose of this study was to provide a theoretical basis for clinical diagnosis by performing a retrospective analysis of the data in the past 14 years. In this study, we retrospectively collected the clinical data of infants aged 0-12 months with malignant solid tumors in Beijing Tongren Hospital Affiliated to Capital Medical University from May 2005 to May 2019. The epidemiology, clinical characteristics, treatments, and prognoses were statistically analyzed. A total of 496 infants (294 males and 202 females) with malignant solid tumors were evaluated. The main period of onset was 1-11 months. The most common tumor was retinoblastoma (RB; 51.8%), followed by hepatoblastoma (HB; 26.6%), neuroblastoma (NB; 10.5%), rhabdomyosarcoma (RMS; 3.4%), malignant renal tumors (3.2%), infantile fibrosarcoma (IFS; 1.6%), malignant teratoma (1.2%), Ewing's sarcoma (ES; 0.8%), medulloblastoma (MB; 0.4%), and inflammatory myofibroblastic tumor (IMT; 0.4%). The median follow-up time was 32 months (range, 2-162 months). At 1, 3, and 5 years, the overall survival rates of all the patients were 97.3%, 89.2%, and 81.1%, respectively, and the event-free survival rates were 94.7%, 84.8%, and 75.8%, respectively. In conclusion, as a special colony, malignant solid tumors in infants are complex, heterogeneous, and relatively rare. The prognosis of RB, HB, NB, RMS, malignant renal tumors, IFS, malignant teratoma, ES, MB, and IMT were excellent owing to timely diagnosis and rational treatment.