A series of B?MFI zeolites were synthesized using a solvent?free method using tetrapropylammonium hydroxide (TPAOH) as a template. XRD, SEM, N₂ adsorption desorption, in situ infrared spectroscopy, and pyridine adsorption infrared spectroscopy were used to characterize the effect of template agent addition on the physicochemical properties of B?MFI zeolites, and the performance of 1?butene double bond isomerization reaction was investigated. The results showed that the addition of template significantly affected the grain size and skeleton boron species content of B?MFI zeolites. When the template agent addition was 4.500 g (n（SiO₂）/n（TPAOH)=11.6）, the B?MFI zeolites obtained had the smallest particle size and the largest number of silicon boron hydroxyl pits, providing more highly active reaction sites. The reaction evaluation results confirmed that when using B?MFI molecular sieve catalyst for the double bond isomerization of 1?butene, the conversion rate of 1?butene was as high as 70.00%, and the selectivity of 2?butene was greater than 99%. The catalyst had excellent stability and showed no signs of deactivation during the evaluation period.