Tai Chi (TC) is a mind-and-body exercise and may improve cognitive functions and cardiovascular outcomes in elderly people. This study aimed to confirm the acute effects of TC training on attention and meditation, perceived stress level, heart rate, oxygenation in blood, and palmar skin temperature in community-dwelling healthy older adults. Twenty older TC practitioners and 20 age- and sex-matched non-practitioners volunteered to join the TC and control groups, respectively. After baseline measurements were taken for each group, the TC group performed a TC form for 10 minutes while their cognitive states and cardiovascular responses were concurrently monitored. The control group rested for the same duration in quite standing. Both groups were then reassessed. The participants’ attention and meditation levels were measured using a single-channel electroencephalographic device; stress levels using Perceived Stress Scale; blood oxygenation and heart rate using an oximeter; and palmar skin temperature using an infrared thermometer. Attention level tended to increase during TC and dropped immediately thereafter ( P < 0.001). Perceived stress level decreased from baseline to posttest in the TC group ( P = 0.005). Heart rate increased during TC (54.3% of maximum heart rate) ( P < 0.001) and decreased thereafter ( P = 0.001). No significant group, time, or group-by-time interaction effects were found in any other outcomes. While TC training could temporarily improve attention and decrease perceived stress levels, it could not improve meditation, palmar skin temperature, or blood oxygenation among older adults.