Abstract: The correlation between galaxy size and halo mass is meticulously examined through the application of galaxy-galaxy lensing techniques. The galaxy samples from Sloan Digital Sky Survey Data Release 7 (SDSS DR7) group catalog are divided into different sub-samples according to their sizes, stellar mass and color. The halo mass of each sub-sample is obtained by modeling the measured excess surface density.Blue or red galaxies do not exhibit a strong correlation between halo mass and galaxy size. The slope of the fitted halo mass to size relation for the blue and red sub-samples are 0.0237^+0.0004_-0.0108 and -0.0023^+0.0002_-0.0054, respectively.The results are compared to those from the Illustris-TNG (The Next Generation Illustris project) hydrodynamic simulations, using the half-stellar mass radius provided by the database.Unlike the observations, the halo mass from simulations does show an increasing trend which mainly caused by the fact that there is positive correlation between stellar mass and galaxy size. While dividing the halo mass by the stellar mass causes this dependence to vanish, the results indicate a similarity to those obtained in this work.