The purpose of the study is to evaluate safety, pharmacokinetics,immunogenicity and efficacy of QLS31903 alone in the treatment of advanced cancer.

Key Inclusion Criteria:

• 18 years or older, 40kg or heavier
• Histologically or cytologically confirmed diagnosis of advanced solid tumor （For phase 1b, patients must have solid tumor with GPC3+ )
• Standard treatment failed or standard treatment intolerant, no standard treatment
• Adequate hepatic, hematologic, and renal function

Key Exclusion Criteria:

• Anti-tumor treatment within 4 weeks prior to the first QLS31903 administration,except a few specific conditions
• Other clinical trial within 4 weeks prior to the first QLS31903 administration
• Receipt of a live or live attenuated vaccine within 30 days prior to the first QLS31903 administration
• Prior treatment targeted on GPC3
• HBsAg/HBcAb positive and HBV-DNA>10,000 copy/mL;HCV-Ab positive and HCV-RNA>1,000 copy/mL
• CNS metastasis (except asymptomatic brain metastases or symptomatic brain metastases after treatment stable for more than 4 weeks) and/or carcinomatous meningitis or leptomeningeal disease