To date, a major issue still hindering the wide-spread applications of pultruded glass fiber reinforced polymer (PGFRP) composites is the poor fire performance. Admittedly, PGFRP composites, as a polymeric material, is naturally flammable. Moreover, the fire performance of PGFRPs can hardly be satisfactorily improved without compromising the mechanical properties of materials, such as using modified resin systems or fire-retardant additives. In this regard, existing design standards (e.g., T/CECS 692 from China, CEN/TS 19101 from Europe, and ASCE 74 from United States) have not provided a reliable fire design method for PGFRP structures that can be readily adopted in practical applications. Therefore, this work was conducted based on fire-resistant coatings to investigate the fire performance of PGFRP beam members. Specially, two types of fire-resistant coatings were used, including cementitious and intumescent coatings, and different coating thickness was investigated. Two types of PGFRP beams are studied, including I- and box-sections. Relatively low load levels were applied to all beams through dead weights. The thermal responses of beams were monitored, and the structural behaviors of those beams were studied in terms of their strength and stiffness degradations.