Objective To evaluate the clinical efficacy of lactulose and mosapride in treatment of senile chronic functional constipation and its concomitant symptoms. Methods A total of 80 elderly patients with chronic functional constipation admitted in our hospital from February to June 2019 were prospectively recruited and randomly divided into lactulose group (n=40) and mosapride group (n=40). The patients in the lactulose group took lactulose orally once a day, 15 ml each time for 4 weeks, and those in the mosapride group took Moxapride citratetablet orally 3 times a day, 5 mg each time for 4 weeks. Wexner constipation score, and scores of self-rating anxiety scale (SAS) and self-rating depression scale (SDS) were recorded in the 2 groups before and after intervention, and the efficiency and changes in clinical signs and symptoms were compared between them. SPSS statistics 23.0 was used for statistical analysis. Intergroup comparison was performed using student′s t test, rank sum test or Chi-square test depending on data types. Results The total effective rate for constipation was 75% (30/40) in the lactulose group, which was significantly higher than that of the mosapride group [35% (14/40), P<0.05]. Lactulose treatment resulted in better scores in defecation frequency [0 (0,1) vs 1 (0,1)points], defecation difficulty [1 (1,2) vs 2 (1.25,3)points], abdominal pain [1 (0,2) vs 2 (1,2)points], and defecation time [1 (1,2) vs 2 (1,2)points] when compared with mosapride treatment (all P<0.05). What′s more, the proportions of the patients having anxiety and/or depression were decreased from 52.50% (21/40) before treatment to 25.00% (10/40) after lactulose treatment (P<0.05), but there was no such change in the mosapride group [70.00% (28/40) vs 52.50% (21/40), P>0.05]. Conclusion To the elderly patients with chronic functional constipation, lactulose significantly alleviates their clinical symptoms and reduces their SAS and SDS scores simultaneously.