Objective: To investigate and explore the changes of the diagnosis of Chinese children with autism spectrum disorder (ASD). Methods: The families of two groups of children aged 1-6 and 6-16 years who were diagnosed with ASD were selected from ALSOLIFE platform, and the online questionnaire was used to investigate the symptoms and its diagnosis related information. ANOVA was applied to compare the mean values, and χ 2 analysis was taken to compare the differences of two groups in the time of finding symptoms, the time of the first diagnosis, the time of treatment, and the diagnosis delayment. Results: The initial recognition age of symptoms was 26.05 months age (2.17 years) in the young group (1-6 years), and 30.76 months age (2.56 years) in the old group (6-16 years). The age of first visit doctor was 28.21 months age (2.35 years) in the young group and 34.29 months (2.86 years) in the old group, while the average delay was only 3.43 months, of which the average delay was 4.52 months in the old group and 2.78 months in the young group. The age of diagnosed as ASD was 38.01 months age (3.17 years) in the young group and 31.07 months age (2.59 years) in the old group, while the average delay from first diagnosis to last diagnosis was 3.16 months. The delay from first diagnosis to last one was 3.71 months age in old age group, and 2.83 for the younger age group, The above differences were statistically significant ( F =328.30, 535.64, 507.71, 103.03, 17.79, P <0.01). Most of the children were still in the top hospitals to get diagnosed, but the role of child care was becoming more and more important. Conclusion The diagnosis efficiency of ASD children has been greatly improved, the time of symptom identification and diagnosis is advanced, and the delay of seeing a doctor and diagnosis is shortened.