[Objective] This study aimed to optimise organic and inorganic mulches suitable for urban bare soil coverage and provide theoretical guidance for urban bare soil management. [Methods] Four types of organic ecological mulches (straw, mushroom residue, sawdust, and pine bark) and four types of inorganic ecological mulches (ceramsite, volcanic stone, perlite, and maifan stone) were used as research objects, and the indoor immersion method was used to compare the water retention effect of the organic and inorganic ecological mulches applied to urban bare soil. Several ecological mulches with good water retention effects were selected. [Results] ① The changing trends of the water-holding capacity and water absorption rate of the organic and inorganic ecological mulches were basically consistent. The water-holding capacity, water absorption rate, and soaking time of the two types of ecological mulches had significant logarithmic and power function relationships, respectively. ② The maximum water-holding capacity and effective storage capacity of the organic ecological mulches were generally higher than those of the inorganic ecological mulches. Among the four types of organic ecological mulches, sawdust and straw had the best (i.e., highest) water-holding capacity and effective storage capacity, followed by mushroom residue and pine bark. Among the four types of inorganic ecological mulches, volcanic rock, perlite, and ceramsite had the best water-holding capacity and effective retaining capacity, and maifan stone had the worst. [Conclusion] In the actual application of urban bare soil coverage, organic ecological mulches (sawdust and straw) and inorganic ecological mulches (volcanic stone, perlite, and ceramsite) with good water retention effects can be selected preferentially when various local natural environmental factors are fully considered.