In this study, colloidal silica-fixed and propionylated dual-treated wood (CSPW) composites were prepared, and flame resistance, color change, strength, and decay resistance evaluated. For comparison, colloidal silica-fixed wood (CSW) and propionylated only-treated wood composites prepared and their properties compared to dual-treated CSPW composites. The results showed that: (1) The oxygen indexes of the CSPW composites were similar to the CSW composites but much higher than those of untreated woods and the propionylated woods, and they increased with an increase in weight percent gain of the colloidal silica fixation (WPGcsi) in the composites, showing an effective reduction in the flammability by the fixation of colloidal silica; (2) CSPW composites showed little or no difference in the modulus of elasticity and modulus of rupture compared with the untreated woods, indicating little or no significant reduction in strength properties of the wood specimens; (3) The color difference of the wood specimens before and after treatment changed slightly; and (4) Minimal weight losses of the CSPW composites occurred upon fungal attack by T. versicolor and F. palustris, showing good decay resistance by propionylation of the composites.