The combined use of gastrointestinal hormones for treating metabolic diseases is gaining increasing attention. It was documented previously that co-administration of a cholecystokinin receptor-1 receptor (CCK-1R) agonist with a glucagon-like peptide-1 receptor (GLP-1R) agonist exerted improved effects on metabolic improvements in obese rodents. Here, we reported a series of novel GLP-1R/CCK-1R co-agonists constructed by linking the C-terminus of a GLP-1R agonist (native GLP-1 or Xenopus GLP-1) to the N-terminus of a CCK-1R selective agonist NN9056. The stability of co-agonists was further enhanced by introducing an albumin binding motif. In vitro functional assays revealed that the co-agonists retained full agonism potency on GLP-1R and CCK-1R. Particularly, 2a and 2c showed higher hypoglycemic and insulinotropic activities than NN9056 and semaglutide. The glucose-lowering durations and PK profiles of 2a and 2c were comparable to those of semaglutide. Desirably, in diet induced obesity (DIO) mice, 2a and 2c exhibited superior metabolic benefits to NN9056 and semaglutide in reducing food intake, inducing body weight loss, and regulating lipid metabolism. In short- and long-term studies in diabetic db/db mice, 2a and 2c showed enhanced effects on HbA1c, glucose tolerance, and pancreas function restoration compared with semaglutide. Importantly, no side effects, toxicities, or pancreatic inflammation were caused by 2a and 2c treatments. These preclinical studies suggest that the pharmacological effects of CCK-1 and GLP-1 pathways can be harnessed in a single fusion peptide, yielding a promising combination therapy strategy for treating metabolic disorders.