Using 3,3′,5,5′⁃tetramethylbiphenol (TMBP), 2⁃(chloromethyl)⁃1,2⁃epoxypropane (MECH), and sodium hydroxide as raw materials, a biphenyl⁃type epoxy resin (3,3′,5,5′⁃tetramethylbiphenyl bisphenol dimethyl glycidyl ether) was synthesized by a two⁃step method. The biphenyl⁃type epoxy resin with relatively low chlorine mass fraction was obtained by removing residual inorganic chlorine in the product using an anion exchange resin. The structure and properties of the samples were characterized using FTIR, 1H NMR, DSC, HPLC, and a rotational rheometer. The influence of different raw material ratios, reaction temperatures, and reaction times on the product yield was investigated through orthogonal experiments. The results show that when the raw material ratio is n(TMBP)/n(MECH)=1.0∶10.0, the reaction temperature in the first stage is 90 ℃, the reaction temperature in the second stage is 80 °C, n(NaOH)/n(TMBP)=2.1∶1.0, and the reaction time in both stages is 4 h, within the selected experimental range, this process condition is relatively optimized. The effective substance mass fraction of the obtained sample is above 85%, the measured epoxy value is 0.5 eq/(100 g), which is relatively close to the theoretical value. The resin exhibits a low melt viscosity of 0.12 Pa·s at 150 ℃, making it suitable for applications such as epoxy encapsulation.