Triaminoguanidinium nitrate （TAGN） was obtained via amination of guanidinium nitrate， and its structure and properties were characterized by elemental analysis， fourier transform infrared spectroscopy （FT-IR）， differential scanning calorimetry （DSC） and scanning electron microscope （SEM）. Short block-like TAGN crystal particles were prepared by ultrasound assissted cooling crystallization in water. The influencing factors of crystal modifier， ultrasonic and cooling process for controlling crystal morphology and particle size， were analyzed by SEM and particle size analysis， and results revealed that ultrasound assissted process can lead to uniform crystalline morphology with narrow particle size distribution. The crystal morphology modifier and temperature control program have a significant effect on the particle size， particle size distribution and crystalline morphology of TAGN. Under the action of ultrasonic （750 W， 20 KHz）， two kinds of high-quality TAGN crystals with uniform crystalline morphology， smooth surface without sharp edge angle， high density and narrow particle size distribution were prepared by using suitable cooling process and PVP K30 （0.03%） as the crystal morphology modifier. Compared with present manufactured raw materials，the comprehensive performance of TAGN have been improved， the characteristic explosion percentage of two kinds of TAGN decreases from 20% to 8% and 4% apart， the characteristic drop height increases 5.9 cm and 3.4 cm apart， the density increases from 1.571 g·cm^-3 to 1.586 g·cm^-3 and 1.589 g·cm^-3 apart， the onset melt point increases from 224.8 ℃ to 227.7 ℃ and 228.2 ℃， respectively. Charging with the prepared product will significantly improve the charging process performance and solid content， so as to improve weapon performance.