Objective　To compare the advantages and disadvantages of three methods in the morphological measurements and explore the morphological characteristics of the tibia medullary cavity in Tibet mini-pigs.　Methods　Tibia specimens were collected from thirty Tibet mini-pigs. Measurement of the length, arc as well as the coronal and sagittal width of the narrowest point of the tibial medullary cavity was carried out through plain radiography and CT 3-dimensional reconstruction or and directly in the specimens Data were recorded and processed using appropriate statistic methods.　Results　The main morphological characteristics of the tibial medullary cavity in Tibet mini-pigs is being triangular and elliptical in shape in the proximal and distal ends, respectively, and being intermediate in shape in the middle segment. The length of the medullary cavity measured by X-ray , CT and specimen were (11.75±0.58)cm, (11.58±0.55)cm and (11.70±0.65)cm, respectively. (P=0.524). Measurements of the coronal width of the narrowest point were 0.88±0.08 cm，0.84±0.06 cm, 0.85±0.07cm , respectively (P=0.032). No significant differences were detected in the measurements of  the arc of tibial medullary cavity (26.89±0.50°，26.06±0.49°， 26.50±0.42°，P=0.106 ).　Conclusion　The accuracy of measurement through CT 3-dimensional reconstruction is higher than that through plain radiography. and the results of measurement through CT 3-dimensional reconstruction is closer to measurement directly performed in specimens. Therefore, data measured through CT 3-dimensional reconstruction are recommended for scientific research. The shape of the tibia medullary cavity in Tibet mini-pigs is similar to the human's, making it suitable for designing new intramedullary nails.