This study compared the absorption of subretinal fluid (SRF) in patients with rhegmatogenous retinal detachment (RRD) with and without high myopia after scleral buckling (SB) and investigated the effect of high myopia on SRF absorption. This retrospective study included patients with primary macula-off RRD grouped according to myopia and age. The optical coherence tomography (OCT) and OCT angiography indicators included subretinal fluid height (SRFH), subfoveal choroidal thickness (SFCT), and choroidal capillary blood flow density (CCFD) measured regularly. The presence of SRF 3 months after surgery was defined as delayed absorption. Overall, 90 eyes of 89 patients were enrolled, and 46 eyes (51.11%) had high myopia. In 43 eyes (47.78%), SRF absorption was delayed. There was no significant difference in SRF absorption after SB between the high and non-high myopia groups; younger patients (<35 years) had a higher probability of delayed absorption (p < 0.05). The SFCT in high myopia was significantly thinner than that in the non-high myopia group (p < 0.05); SFCT and SRFH were positively correlated (rs = 0.275, p = 0.002), and there was a significant difference between the average CCFD with and without SRF (p < 0.05). High myopia had no significant effect on SRF absorption after SB.