Abstract: The present disclosure relates to a pulverulent composition comprising (a) at least one phosphate flame retardant synergist selected from hydrogen phosphate salt, dihydrogen phosphate salt, hydrate thereof and mixture thereof; (b) at least one flame retardant; and (c) at least one thermoplastic polymer. The present disclosure also relates to a 3D-printed object formed from the pulverulent composition and a process of forming 3D-printed object. The pulverulent composition shows good printability and the 3D-printed objects obtained from the thermoplastic powders not only have excellent flame-retardant performance but also have good mechanical properties.