diff --git a/yuthon_salary/wizard/salary_compute_wizard.py b/yuthon_salary/wizard/salary_compute_wizard.py
index 24025c7cc..018d8b10c 100644
--- a/yuthon_salary/wizard/salary_compute_wizard.py
+++ b/yuthon_salary/wizard/salary_compute_wizard.py
@@ -138,6 +138,13 @@ class SalaryComputeWizard(models.Model):
                         '工龄工资': 'seniority_salary',
                         '工会会费': 'union_dues',
                     }
+                    # 提前获取基本工资的原始值（处理前）
+                    base_salary_original = 0
+                    for line in internship_id.line_ids:
+                        if line.name == '基本工资':
+                            base_salary_original = line.total
+                            break
+
                     for line in internship_id.line_ids:
                         if line.name in target_names:
                             field_name = target_names[line.name]
@@ -160,8 +167,7 @@ class SalaryComputeWizard(models.Model):
                                 else:
                                     result = rounded_value * 0.8 * internship_days / days
                             elif field_name == 'union_dues':  # 单独处理工会会费
-                                base_salary = getattr(internship_id, 'base_salary', 0)
-                                result = base_salary / 0.8 * 0.05
+                                result = base_salary_original * 0.05
                             else:
                                 if work_days != days:
                                     result = line.total * 0.8 * internship_days / days + line.total * work_days / days