The present disclosure provides a crystalline form of an opioid receptor (MOR) agonist and a manufacturing method thereof. Specifically, the present disclosure provides a crystalline form III of (1S,4S)-4-ethoxy-N-(2-((R)-9-(pyridin-2-yl)-6-oxaspiro[4.5]dec-9-yl)ethyl)- 1,2,3,4-tetrahydronaphthalen-1-amine fumarate and a manufacturing method thereof. The crystalline form III of a compound of formula (I) of the present disclosure has good stability and can be better used for clinical treatment.本公開提供一種鴉片類物質受體(MOR)激動劑的結晶形式及製備方法。具體地，本公開提供(1S,4S)-4-乙氧基-N-(2-((R)-9-(吡啶-2-基)-6-氧雜螺[4.5]癸-9-基)乙基)-1,2,3,4-四氫萘-1-胺富馬酸鹽的III晶型及其製備方法。本公開式(I)化合物的III晶型具備良好的晶型穩定性，可更好地用於臨床治療。
