［Objective］ To further improve the etch resistance and thermal stability of printed circuit board（PCB） solder resist inks.［Methods］ Four alkaline-soluble fluorene-based epoxyacrylates modified with different anhydrides（maleic anhydride（MA）phthalic anhydride（PA），methyl nadic anhydride（MNA），andtetrahydrophthalicanhydride（THPA））were synthesized. The structuresof the four epoxy acrylates were characterized using Fourier transform infrared（FT-IR）spectroscopyand proton nuclear magnetic resonance（¹H NMR） and their basic properties were systematicallyinvestigated. Among them，the THPA-modified alkali-soluble fluorene-based epoxy acrylate（FATH） demonstrated excellent photosensitivity，thermal resistance，and mechanical properties. Therefore，the influence of FATH addition amount on the etch resistance and thermal stability of the solder resist inkwas further explored.［Results］Increasing the mass ratio of FATH could effectively improve both etchresistance and thermal stability of the solder resist ink. When the mass ratio of FATH to commercial o-cresol novolac epoxy resin（R5185）reached 3∶2，the onset thermal decomposition temperature of the solder resist ink increased from 365. 33 ℃（without FATH）to 372.67℃，while the side etching of developed lines decreased from 44. 2 μm（without FATH） to 37.4μm，achieving a development resolution of 50 μm.［Conclusion］This work will effectively promote the development of novel PCBsolder resist inks with high etch resistance and thermal stability.