Chinese cities need a sustainable, compact spatial layout. Therefore, comprehensive measurement of the urban spatial form is of great significance. This paper introduces the degree of dispersion (DIS), assesses the advantages and disadvantages of DIS through 6 situations, and identifies the deficiency of DIS value in reflecting the compactness of urban morphology, and then put forward a new compact index to assess urban spatial form, that is, the normalized dispersion index NDIS. NDIS is not affected by the size of the urban area, and the city has a unique value, which is conducive to the horizontal and vertical comparison of urban compactness. The greater the NDIS value, the more discrete the city is. Furthermore, NDIS is combined with the normalized compactness index NCI to analyze the compactness of 35 cities in China. The results show that:(1) The maximum NDIS value for the investigated 35 cities is 1.64, the minimum is 1.14, and the average is 1.29 ±0.12 (SE). (2) Values of NCI ranges between 0.1-0.39, with an average of 0.24 ±0.07 (SE). (3) NDIS and NCI have a moderate degree of correlation (r=-0.44, P < 0.01), but NDIS is more accurate in expressing the distance between urban patches. (4) The correlation shows that the two indices have partially overlapping information, but the difference can better highlight the urban morphological characteristics. Of course, NDIS is not a perfect index to measure the urban spatial morphology. A more accurate and comprehensive measurement of the spatial patterns of Chinese cities requires the combination of more landscape metrics. The next step in research would be to focus on combining compactness indices with urban structure and environmental factors to find out the suitable ranges for Chinese cities and provide a guideline for the construction of the compact city, sustainable city, and low carbon city.