The present invention relates to a new crystalline polymorph of 3-( N- methyl- N- pentyl) amino-1-hydroxypropane-1,1-diphosphonic acid monosodium salt monohydrate (Ibandronate) with the following formula本發明係關於一種下式之單水合3-(N-甲基-N-戊基)胺基-1-羥丙烷-1,1-二膦酸單鈉鹽(伊班膦酸鹽(Ibandronate))之新型結晶多晶型物 式I;;及其製備方法。