Inclusion Criteria:  Subjects will be enrolled into the study only if they meet all of the following inclusion criteria:  Subjects who are fully informed of the purpose, nature, method and possible adverse reactions of the study, and are willing to participate in the study and sign the informed consent document prior to any procedure; Aged between 18 to 75 years old, male or female when sign the Informed consent form (ICF);  Subjects who meet the criteria:  Phase I dose escalation:  Part Ia: Subjects have histological or cytological confirmation of recurrent or refractory advanced solid tumors, and are intolerable for available standard therapy, or there is no available standard therapy.  Part Ib:Subjects have been histologically or cytologically confirmed advanced solid tumors and meet the criteria as follows: No previous systemic chemotherapy was given for the recurrent or metastatic disease or for the subjects who have received curative treatment (including neo-adjuvant or adjuvant chemotherapy /radiotherapy, etc.), the interval between recurrence and the last dose of previous anti-cancer treatment must be more than 6 months.  Phase II dose expansion: subjects with positive CLDN18.2 confirmed by central immunohistochemistry (IHC).  Part IIa: Subjects have histological or cytological confirmation of recurrent or refractory advanced solid tumors, and are intolerable for available standard therapy, or there is no available standard therapy.  Part IIb: Subjects have histological or cytological confirmation of advanced solid tumors and meet the criteria as follows: No previous systemic chemotherapy was given for the recurrent or metastatic disease, or for the subjects who have received curative treatment (including neo-adjuvant or adjuvant chemotherapy /radiotherapy, etc.), the interval between recurrence and the last dose of previous anti-cancer treatment must be more than 6 months;  At least one evaluable lesion for phase I and one measurable lesion for phase II according to RECIST v1.1; ECOG score 0-1; Life expectancy ≥ 3 months; Subjects must have the following organ and marrow function in laboratory tests within 7 days prior to the first dose; Subjects who are able to well communicate with investigators as well as understand and adhere to the requirements of this study.  Exclusion Criteria:  Subjects will be excluded from the study, if they meet any of the following criteria:  Child-bearing potential female who have positive results in pregnancy test or are lactating; Subjects who known to be allergic to the similar products or any of its excipients; Exposure to any IMP, or participate in any other clinical trial within 21 days prior to 1st dosing of LM-102; Subjects with anti-tumor treatment within 28 days prior to 1st dosing of LM-302, including radiotherapy, chemotherapy, biotherapy, endocrine therapy and immunotherapy, etc. Subjects who have received surgical or interventional treatment within 28 days prior to 1st dosing LM-102, with the exception for tumor biopsy, puncture, etc.; Subjects who have received the treatment targeting to CLDN18.2 or ADCs; Use of any live vaccines (e.g., against infectious diseases such as influenza, varicella etc.) within 28 days prior to 1st dosing of LM-102; Subjects with the history of interstitial lung disease or drug-induced interstitial lung disease/pneumonitis; Subjects who are taking therapeutic doses of anticoagulants such as heparin or vitamin K antagonists (except for preventive treatment at a stable dose); Subjects with gastric outlet obstruction, persistent recurrent vomiting or uncontrolled/severe gastrointestinal hemorrhage, or ulcer within 28 days prior to 1st dosing; Subjects who are unable to take the oral drugs, have the conditions that severely affect gastrointestinal absorption; Subjects with known central nervous system (CNS) or meningeal metastasis; Subjects who have uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures; Subjects who have severe cardiovascular disease; Any adverse event from prior anti-tumor therapy has not yet recovered to ≤ grade 1 of CTCAE v5.0; Subjects with uncontrolled tumor-related pain. Subjects who have uncontrolled or severe illness, including but not limited to ongoing or active infection requiring antibiotics administration; Subjects who have a history of immunodeficiency disease, including other acquired or congenital immunodeficiency diseases, or organ transplantation, or allogeneic bone marrow transplantation, or autologous hematopoietic stem cell transplantation; HIV infection, active HBV and HCV infection; Men and women who are unwilling to use appropriate contraceptive methods throughout the study period and for at least 6 months after the last use of LM-102; Subjects who have psychiatric illness or social situations that would preclude study compliance; Subjects who have another active malignancy which is likely to require treatment, and have the history of another malignancy within 2 years before the first dosing; Subject who is determined as not eligible to participate in this study by the investigator.