The exhaust emissions from ship diesel engines contain a large amount of carbon dioxide, which is one of the main greenhouse gases. Currently, carbon capture and storage (CCS) technology is considered a promising means of reducing CO₂ emissions. In the process of carbon dioxide capture, the chemical absorption method is the most widely used. Based on the main characteristics of various absorbents at present, this article selects MEA and NaOH solutions as representative absorbents to compare the carbon dioxide capture effect, aiming to establish an efficient and low-cost absorption and desorption cycle system. This article uses Aspen Plus software to simulate the performance of common absorbents, MEA and NaOH solutions, in carbon dioxide capture systems. Comparative analysis of carbon dioxide capture efficiency from various aspects is performed, such as intake temperature, pressure, flow rate, carbon dioxide concentration, absorbent concentration, reflux ratio, etc. The research results show that the performance of NaOH solution in absorbing CO₂ is similar to that of MEA under the same capture environment. Under absorption conditions of 40ºC and 1.5 bar, the highest capture rate can reach about 76%. Combining the economic costs of the two types of absorbent solutions, the economic cost of using NaOH solution as the absorbent is only one-third of that of MEA solution. In contrast, using NaOH solution as an absorbent is more cost-effective and conducive to large-scale market promotion when the CO₂ capture effect is equivalent.