Provided in the present invention are a compound PAC-1 in amorphous form, an oral pharmaceutical composition comprising the compound PAC-1 in amorphous form, and a use of the compound PAC-1 in amorphous form in the preparation of the oral pharmaceutical composition. The PAC-1 in amorphous form displays an obviously lower neurotoxicity than PAC-1 in crystal form, and is more suitable for being used to develop drugs for treating diseases such as tumours, especially metastatic tumours and the like.