Objective To investigate the utility of Methylene Blue staining combined with light transmission method, hereinafter referred to as light transmission and staining method, for endoscopy-pathological comparison observation in endoscopic submucosal dissection (ESD) for early gastric cancer. Methods From October 2021 to August 2023, a total of 75 patients undergoing ESD treatment for early gastric cancer were selected for the study. The traditional methods, light transmission and staining methods were utilized successively by the same doctor, to show the demarcation line (DL), irregular microvascular pattern (IMVP) and irregular microsurface pattern (IMSP) of the lesion, and compare the differences between histological types. Furthermore, the positive rate of surgical margin, the detection rate of undifferentiated cancer components, multifocal lesions and Lymphovascular Invasion (LVI) were analyzed between the 88 cases of pathological results obtained by traditional methods as control. Results Using the light transmission and staining method, DL was detected in 96.0%, which is higher than 72.0% using the traditional method (P＜0.01). IMVP and IMSP were observed in 89.3% (67/75) and 100% (75/75) using the light transmission and staining method, while they could not be found using the traditional method. In contrast to the topographic mapping, there was no statistical difference in the coincidence rate of endoscopy and pathology between differentiated type, undifferentiated type and mixed type (89.1%、50%、77.8%, P =0.101). To compare with 88 cases using traditional method sampling, this method can help to find undifferentiated cancer and reduce the false positive rate of surgical margins (P=0.026, P=0.032), but no statistical difference in the rate of finding multiple lesions and LVI. Conclusion It serves as a communication bridge between endoscopy and pathology. By showing DL, IMVP and IMSP, this novel method can improve pathologists' ability to recognize lesions during sampling, more likely to detect undifferentiated cancer and reduce false positive of margin, and verify endoscopist judge accuracy for the lesions' nature and border, and improve the overall efficiency of lesion recognition in clinical practice.