“国防预算”的英文表达是 "defense budget"（美式英语）或 "defence budget"（英式英语）。
1、 The government plans to increase the defense budget next year to modernize its military equipment.
（政府计划明年增加国防预算，以实现军事装备现代化。）
2、 The defence budget accounts for a significant portion of the country's annual expenditure.
（国防预算在该国年度支出中占据重要比例。）